1. Field of the Invention
This invention relates to packages to encase one or more semiconductor devices, and more particularly to a molded plastic ball grid array package have a substrate base and a heat slug.
2. Description of the Related Art
Enhancing the thermal performance of substrate-based packages for encasing semiconductor devices remains a challenge. Typical substrate-based packages such as land grid array and ball grid array packages typically extract heat through metallic vias. However, the small surface area of the vias limits the amount of heat that is dissipated. It is known to enhance the thermal dissipation of a surface mount package by brazing a heat sink to an aperture extending through the package base as disclosed in U.S. Pat. No. 5,111,277 to Medeiros et al. A package substrate including heat sink is also disclosed in U.S. Pat. No. 5,629,835 to Mahulikar et al. Both U.S. Pat. No. 5,111,277 and U.S. Pat. No. 5,629,835 are incorporated by reference in their entireties herein.
A method for enhancing the electrical properties of a molded plastic package by reducing self and mutual inductance is disclosed in U.S. Pat. No. 5,559,306 to Mahulikar. Parallel metallic plates are disposed within the package body with a semiconductor device disposed therebetween. U.S. Pat. No. 5,559,306 is incorporated by reference in its entirety herein.
There remains, however, a need for a substrate-based package with improved thermal dissipation that may be manufactured in large quantities at low cost.